The find familiar spell enables the caster to attempt to summon a familiar to act as his aide and companion. Familiars are typically small creatures, such as cats, frogs, ferrets, crows, hawks, snakes, owls, ravens, toads, weasels, or even mice. A creature acting as a familiar can benefit a wizard, conveying its sensory powers to its master, conversing with him, and serving as a guard/scout/spy as well. A wizard can have only one familiar at a time, however, and he has no control over what sort of creature answers the summoning, if any at all come.
Note: This version of find familiar originally appeared in the 2nd Edition Player's Handbook for Advanced Dungeons & Dragons from TSR. Its use here is for the purposes of providing context for the campaign only.